Retrofit recessed fluorescent strip fixture and method

ABSTRACT

A retrofit fixture for installation into an existing recessed fluorescent strip fixture in an inverted T-bar grid ceiling. The retrofit fixture length is less than the length of the ceiling opening, except for hangar tabs which extend from a flange along a longitudinal edge. The fixture may be hung from the ceiling grid members by the tabs while wiring connections are made, and then swung into place. Lamps having a combined length greater than the length of the ceiling opening may be used by placing the lamp holders in a staggered arrangement.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to recessed fluorescent striplighting fixtures. More particularly, this invention relates to aretrofit recessed fluorescent strip fixture which is easily installablefrom below the plane of the ceiling into existing recessed fluorescentstrip lighting fixtures to enable the use of smaller, more efficient,brighter fluorescent light tubes with better color rendering.

[0003] 2. Description of Prior Art

[0004] Higher efficiency, brighter fluorescent light tubes with bettercolor rendering are the results of recent development in fluorescentlighting technology. Particularly, these developments have resulted inthe availability of T-8 technology tubes with the performance describedabove. These developments have been of particular interest to largeusers of recessed strip fluorescent fixtures, such as department,grocery and other retail stores.

[0005] Strip fluorescent fixtures are commonly utilized in continuousrows to provide economical uniform lighting of large indoor spaces, suchas retail stores. Recessing the fixtures above the plane of the ceilingprovides for a ‘cleaner’ look and more visual comfort than ‘open’ stripfixtures. In the past, these fixtures typically utilized T-12 sizedtubes in 8 foot lengths. The fixtures themselves typically measured 1foot by 8 foot and were installed into inverted “T” (NEMA “G”) ceilingsystems.

[0006] Retail stores desire the ability to more efficiently andeffectively illuminate their merchandise and their stores by utilizingthe newer technology fluorescent light tubes. However, the newertechnology tubes cannot be installed into existing strip fixtures asthey require different lamp sockets and ballasts.

[0007] Replacement of existing fixtures would be very costly, requiringthe purchase of completely new fixtures, wiring and construction costsof removing the old fixtures and installing the new fixtures, and, mostimportantly, the inconvenience and cost of closing down sections of thestore as the construction proceeds creating a “hard hat area”.

SUMMARY OF THE INVENTION

[0008] Thus, it is an object of the present invention to provide aneconomical retrofit recessed fluorescent strip fixture using T-8technology tubes installable from below the plane of the ceiling intoand utilizing the housing of older strip fixtures using T-12 sizedtubes.

[0009] It is also an object of the present invention that the retrofitfixture utilize the wiring from the old fixture.

[0010] It is another object of the present invention that the retrofitfixture be easily installable by one person in a relatively short periodof time without the use of fasteners or tools.

[0011] It is a further object of the present invention to provide afixture that may be shipped and installed with lamps already in theirsockets to further reduce installation time.

[0012] These and other objects are achieved through the use of aretrofit fixture which is installable into an existing recessedfluorescent strip fixture in an inverted T-bar grid ceiling. Theretrofit fixture has a reflector sized to fit within the existingfixture and within a grid opening in the ceiling. Flanges are locatedalong the longitudinal edges of the retrofit fixture, with one flangefurther having hangar tabs extending from its ends.

[0013] By making the reflector flexible about its longitudinal axis, thewidth of the reflector and the flanges may be reduced to an amount lessthan the width of the ceiling opening for installation, but return to awidth where the flanges cooperate with the ceiling members to supportthe retrofit fixture within the existing fixture.

[0014] Lamp holders may be in a staggered arrangement on the reflectorto support lamps having a combined length greater than the length of theceiling opening.

[0015] All of the above outlined objectives are to be understood asexemplary only and many more objectives of the invention may be gleanedfrom the disclosure herein. Therefore, no limiting interpretation of theobjectives noted are to be understood without further reading of theentire specification and drawings included herewith

DESCRIPTION OF THE DRAWINGS

[0016]FIG. 1 shows a bottom view of a T-8 retrofit recessed fluorescentstrip fixture of the present invention installed in a ceiling and oldrecessed fixture.

[0017]FIG. 2 shows a perspective view of a T-12 recessed fluorescentstrip fixture with the T-12 tubes and ballast cover removed.

[0018]FIG. 3 shows a bottom view of a T-8 retrofit recessed fluorescentstrip fixture of the present invention.

[0019]FIG. 4 shows an end view of the fixture of FIG. 3.

[0020]FIG. 5 shows a perspective view of a T-8 retrofit recessedfluorescent strip fixture of the present invention hanging from a “T”bar ceiling grid under a T-12 recessed fluorescent strip fixture.

[0021]FIG. 6 shows a detail perspective view of the wiring of a T-8retrofit recessed fluorescent strip fixture of the present invention tothe wiring of a T-12 recessed fluorescent strip fixture.

[0022]FIG. 7 is an illustration of the step of swinging a T-8 retrofitrecessed fluorescent strip fixture of the present invention intoposition.

[0023]FIG. 8 shows a sectional view of the fixture taken along the line8-8 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0024] As shown in FIG. 1, the retrofit recessed fluorescent stripfixture of the preferred embodiment has a low profile reflector 10which, when installed, is recessed above the plane of the ceiling. Theceiling plane is defined by an inverted “T” (NEMA “G”) ceiling systemhaving “T” bars 12 in a grid pattern.

[0025] Also shown in FIG. 1, the fixture of the preferred embodiment has2 pairs of T-8 size fluorescent tubes 14, 16 and 18, 20, with each tubebeing one-half the length of the T-12 size tubes of the old fixture. Ina typical 1 foot by 8 foot unit, the “T” bars 12 at the end of thefixture will be spaced 96 inches on-center L_(C), with the length of thesupport portion of the “T” bar W_(B) being 1 inch wide. Thus, the widthof the opening between the end “T” bars L_(O) is 95 inches. Further, anyretrofit fixture installable from below the plane of the ceiling intothe existing recessed fixture must have a length less than the width ofthe opening L_(O).

[0026] The length of an 8 foot T-8 tube assembly, including the lampholders, is approximately 96 inches. Since the tubes of fluorescentstrip fixtures by design are parallel to the sides of the fixture, it isnot possible to utilize an 96 inch tube assembly in the 95 inch openingL_(O) available from below the plane of the ceiling.

[0027] The preferred embodiment, shown in FIG. 1, overcomes thislimitation through the use of pairs of 48 inch T-8 tubes 14, 16 and 18,20, held by lamp holders 32 and staggered such that the tube assemblyends overlap slightly at the center of the fixture. Thus, the retrofitfixture of the preferred embodiment will fit lengthwise in the 95 inchopening L_(O).

[0028] The principles applied with respect to the 1 foot by 8 foot unitof the preferred embodiment apply equally to other commonconfigurations, including 1 foot by 4 foot, and 1 foot by 16 footconfigurations.

[0029] Installation of the T-8 retrofit fixture of the preferredembodiment into the T-12 fixture is illustrated in FIG. 2 through FIG.5. The steps are as follows.

[0030] First, power must be disconnected to the T-12 fixture. Then theexisting T-12 tubes, and the ballast cover of the T-12 fixture removed,leaving the T-12 lamp holders 22 and T-12 ballast 24 exposed within theT-12 fixture housing 26, as shown in FIG. 2.

[0031] As shown in FIG. 3, the retrofit fixture of the preferredembodiment has hangar tabs 28 extending from flange 30 located along aside edge of the retrofit fixture. Also shown in FIG. 3, the retrofitfixture of the present invention may be shipped and installed with theT-8 fluorescent tubes 14, 16, 18, and 20 already installed in T-8 lampholders 32.

[0032] Electronic T-8 ballast 40 is attached to the top side of thereflector 10, as shown in FIG. 4.

[0033] The next installation step is to hang the retrofit fixture fromthe “T” bar grid 12 by hangar tabs 28. This can be accomplished byinserting the retrofit fixture side edge having the hangar tabs 28 tothe T-12 fixture housing 26 diagonally across the opening in the “T” bargrid until the hangar tabs 28 are above the plane of the ceiling. Thenthe retrofit fixture can be straightened and pushed to the side, asshown in FIG. 5, so that the retrofit fixture will hang from hangar tabs28 supported by the end “T” bars 12 _(LE) and 12 _(RE).

[0034] The hangar tabs 28 can be formed as a short extension of the 22gauge material utilized for the reflector 10 and flange 30, extendingapproximately ½ inch long and ¼ in wide. When the fixture is hanging, asshown in FIG. 5, the hangar tabs 28 will be in shear, adequatelysupporting the weight of the retrofit fixture while the one-maninstaller makes the following wiring connections.

[0035] As shown in FIG. 6, power supply leads 42 can be cut from theT-12 ballast 24 and attached to the power supply leads 44 from the T-8ballast 40. Fixture and ballast grounds 46 from the T-12 and T-8fixtures and ballasts can also be cut and attached.

[0036] As shown in FIGS. 7 and 8, after the wiring connections arecomplete, the installer may then swing the retrofit fixture up intoplace transferring the weight of the fixture from the hangar tabs 28 tothe flange 30 supported by the side “T” bar 12 _(RS) as it is slid underthe flange 48 of the T-12 fixture. The retrofit fixture reflector 10 maythen be flexed just enough to slide flange 30′ along the other side edgeof the retrofit fixture between flange 48′ of the T-12 fixture and theother side “T” bar.12 _(LS).

[0037] As shown in FIG. 8 the depth of the older T-12 fixture housing 26allows the low profile reflector 10 of the T-8 retrofit fixture, alongwith T-8 ballast 40, T-8 lamp holders 32 and T-8 fluorescent tubes 14,16, 18 and 20 to be installed into the T-12 fixture, utilizing the T-12fixture as its housing. This installation can be accomplished by oneperson from below the plane of the ceiling within a 5-8 minute timeframe per unit. Because the T-12 fixture does not have to be removed,the retrofit can be accomplished with minimal disruption and expense.

[0038] This detailed description, and particularly the detailedmeasurements and component descriptions of the preferred embodiment, isgiven primarily for clearness of understanding and no unnecessarylimitations are to be understood therefrom for modifications will becomeobvious to those skilled in the art upon reading this disclosure and maybe made without departing from the spirit of the present invention.

What is claimed is:
 1. A retrofit light fixture, comprising: a lowprofile reflector having a first and a second side edge, said reflectorbeing generally concave in shape; a ballast; a plurality of lamp holdersconnected electrically to said ballast; wherein said retrofit fixturefits within a reflector chamber of an existing light fixture and isretained therein.
 2. The retrofit light fixture of claim 1 furthercomprising a first and a second hangar tab on said first side edge ofsaid housing.
 3. The retrofit light fixture of claim 2 wherein saidfirst and said second hangar tabs are at opposite distal ends of saidfirst side edge.
 4. The retrofit light fixture of claim 1 wherein saidplurality of lamp holders are in staggered offsetting relationship. 5.The retrofit light fixture of claim 4 wherein said plurality of lampholders are further comprised of four pairs of opposing lamp connectors.6. The retrofit light fixture of claim 1 wherein said first and saidsecond side edge are comprised of a first flange on said first side edgeand a second flange on said second side edge.
 7. The retrofit lightfixture of claim 6 wherein said first and said second flange of saidreflector on said first and said second side edge are compressed againsta first and a second flange on said existing fluorescent light fixture.8. A retrofit light fixture in combination with an existing recessedfluorescent strip fixture, comprising: an existing fluorescent lightfixture reflector defining a reflector chamber; a low profile retrofitreflector fitting within said existing fixture reflector chamber;wherein said retrofit reflector has a plurality of paired lamp holderselectrically connected to a ballast.
 9. The retrofit light fixture ofclaim 8 wherein said retrofit reflector is comprised of a concavereflector having a first and a second side edge.
 10. The retrofit lightfixture of claim 9 wherein said retrofit reflector has a first and asecond tab on said first side edge, said first and said second tabsbeing at opposite distal ends of said first side edge.
 11. The retrofitlight fixture of claim 10 wherein said existing fixture reflector has afirst and a second flange, said first side edge of said retrofitreflector adjacent to said first flange, and said second side edge ofsaid retrofit reflector adjacent said second flange.
 12. The retrofitlight fixture of claim 8 wherein said existing fixture reflector has afirst pre-defined length and wherein said retrofit reflector has asecond pre-defined length, said second pre-defined length being lessthan said first pre-defined length.
 13. The retrofit light fixture ofclaim 8 wherein said plurality of paired lamp holders are in a parallelarrangement.
 14. A retrofit fixture for installation into an existingrecessed fluorescent strip fixture, said retrofit fixture comprising: areflector sized to fit within said existing fixture and within a gridopening in said ceiling, said reflector having a first longitudinal edgeand a second longitudinal edge; a first flange extending from said firstlongitudinal edge; a hangar tab extending from each end of said firstflange; and a second flange extending from said second longitudinaledge.
 15. The retrofit fixture of claim 14 wherein said reflector isflexible about its longitudinal axis.
 16. The retrofit fixture of claim14 , said reflector further having at least one lamp holder to supportat least one lamp.
 17. The retrofit fixture of claim 16 wherein saidreflector has a plurality of lamp holders arranged to hold a pluralityof lamps of length less than the length of said ceiling opening.
 18. Theretrofit fixture of claim 17 wherein said lamp holders hold said lampsin a staggered arrangement.
 19. The retrofit fixture of claim 18 whereinsaid lamps are T-8 fluorescent lamps.
 20. The retrofit fixture of claim14 further having a ballast attached to the top side of said reflector.21. A retrofit fixture for installation into an existing recessedfluorescent strip fixture in an inverted T-bar grid ceiling having anopening having a predetermined length, said retrofit fixture comprising:a reflector having a length less than said predetermined length, saidreflector having a first longitudinal edge and a second longitudinaledge; a first flange extending from said first longitudinal edge; ahangar tab extending from each edge of said first flange such that thelength of said flange and said hangar tabs is greater than saidpredetermined length; a second flange extending from said secondlongitudinal edge; and a plurality of lamp holders attached to saidreflector arranged to support at least one lamp.
 22. The retrofitfixture of claim 21 wherein said plurality of lamp holders in astaggered arrangement to support at least two lamps having a combinedlength greater said predetermined length.
 23. The retrofit fixture ofclaim 21 , said first flange and said second flange cooperating withsaid inverted T-bar grid ceiling to support said retrofit fixture withinsaid existing fixture.
 24. The retrofit fixture of claim 23 wherein saidreflector is flexible about its longitudinal axis, whereby the width ofsaid reflector with said first and second flanges may be reduced to anamount less than the width of said ceiling opening.
 25. A method ofretrofitting an existing fluorescent strip fixture in an inverted T-bargrid ceiling, comprising the steps of: a. removing the fluorescent lampsand the ballast cover from the existing fluorescent strip fixture; b.partially inserting a retrofit fixture diagonally through an opening insaid grid ceiling and partially into said existing fixture, saidretrofit fixture comprising: a reflector sized to fit within an openingin said grid ceiling and within said existing fixture, said reflectorhaving a first longitudinal edge and a second longitudinal edge, saidreflector being flexible about its longitudinal axis; a first flangeextending from said first longitudinal edge; a hangar tab extending fromeach end of said first flange; a second flange extending from saidsecond longitudinal edge; and a ballast attached to said reflector; c.hanging said retrofit fixture from grid members of said ceiling by saidhangar tabs; d. attaching power supply leads from said existing fixtureto said ballast; e. swinging said retrofit fixture into place withinsaid existing fixture by slightly flexing said reflector such that thewidth of the reflector combined with said first and second flanges maybe reduced to an amount less than the width of said ceiling opening; f.allowing said reflector to return to its original width such that saidretrofit fixture is supported by said ceiling grid members along saidfirst and second flanges.
 26. The retrofitting method of claim 25wherein said retrofit fixture further has at least one pre-installedlamp.